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Dimethyl ether (RE170) is a very important chemical compound, largely employed in the chemical industry, but the available literature data for this fluid, especially in terms of liquid density, are scarce. In this paper, compressed liquid density data were measured along eight isotherms between (283.15 and 353.15) K up to 35 MPa with a vibrating tube densimeter (Anton Paar DMA 512) and, on the basis of these data, the saturated liquid densities were estimated. The overall estimated uncertainty for the density data is within ± 0.1 %. The experimental compressed liquid density data and the estimated saturated density data were correlated by means of fitting equations that are also presented in this paper.

Vapor−liquid equilibria (VLE) data for the difluoromethane (R32) + dimethyl ether (RE170) system were measured with the aim of completing our study of hydrogen bonding between hydrofluorocarbons (HFCs) and dimethyl ether. The measurements were taken in an apparatus based on a static analytical method at temperatures ranging between (258.15 and 293.15) K. The R32 + RE170 system shows a slight negative deviation from Raoult's law that is attributed to hydrogen bonding between RE170 and R32. This H bonding was estimated using the homomorphic concept. The physical interaction was represented by the difference between the excess Gibbs energy (g^E) of R32 + RE170 and its corresponding homomorphic system, the R32 + propane (R290) system. The VLE data were reduced by means of the Carnahan−Starling−De Santis (CSD) equation of state (EoS) together with the classical mixing rule and then by means of the Redlich−Kwong−Soave (RKS) EoS, with the Huron−Vidal mixing rule, using the NRTL equation for g^E at infinite pressure. VLE data for the R32 + RE170 system are not reported elsewhere in the literature.

Semiempirical molecular orbital methods were used to simulate the molecular structure and electronic spectra of a series of triazolephthalocyanines (Tpcs). All molecular studies are in agreement with an aromatic macrocycle where a hypothetical substitution on both triazole and meso nitrogens of the core causes a partial breakdown in the Gouterman's four level model. Minor effects are predicted for the substitution in the isoindole subunit.Comparison between the experimental and theoretical UV–VIS spectra of different metal substituted triazolephthalocyanines is also made.

New derivatives (5-8) of 5-amino-8-hydroxy-1,4-naphthoquinone (1) have been synthesized and characterized by IR, UV-Vis, 1H NMR, mass spectra and CNH. These new ligands and the 5-amino-8-hydroxy-l,4-naphthoquinone (1), the 5-amino-6-bromo-8-hydroxy-1,4-naphtho-quinone (2), the 5-acetylamino-8-hydroxy-1,4-naphthoquinone (3) and the 5-dodecanoylamino-8-hydroxy-1,4-naphthoquinone (4), were complexed with Ni(II) giving the chelates (1a-8a). The structure and site of coordination of these complexes are discussed in relation to their spectroscopic data and thermal analysis.

The study of peroxovanadium compounds has received renewed attention since the discovery of their insulin mimetic properties and of the vanadium bromoperoxidase enzyme which catalyzes the oxidation of halides by hydrogen peroxide. This work presents the synthesis and characterization of three novel oxodiperoxovanadium complexes, Kn[VO(O2)2AA] 2H2O, where AA = L-asparagine(l), L-phenylglycine(2), D, L-homocystine(3). The products were synthesized by the reaction of V2O5, with the amino acid and H2O2 at room temperature. The compounds obtained are yellow, soluble in water and insoluble in organic solvents. They show remarkable hygroscopic character and are light and temperature sensitive. IR and UV-VIS spectra of the compounds show the typical oxo and diperoxo bands (νv = o = 970 cm-1, νvo-o = 870cm-1, νv-O2 = 630, 525 cm-1, ⋋ ≅320nm). The ligand bonding properties were determined on the basis of electric conductivity and spectroscopic data (IR, 1H NMR) as well as elemental analysis.

Diels‐Alder reaction between the naphthoquinones (I) and the butadienes (II) yields the adducts (III) and/or (IV), the regioselectivity being dependent on the substituents.

Oxidation of the acetylaminohydroxyanthraquinone (I) with lead tetraacetate (II) gives the 4a‐acetoxy derivative (III) which is converted to the 3‐substituted anthraquinones (V).

With a view to the synthesis of anthracyclinone systems, Diels‐Alder reactions of the triones (IIa) and (IIb) with various substituted dienes are investigated.